NEARLY six years after Sept. 11, 2001 , what’s striking is how little has changed in America — and in its war effort. And yet if we can’t change ourselves, what are the chances that we can change others?

When President Bush declares that the Global War on Terror is “the concentrated work of generations,” one has to wonder if he really means it. Certainly there’s been little concentration on effective war mobilization, and other countries have noticed.

As we look back to study wars that the United States has won — and why — the most obvious metric is the size of the force that Uncle Sam put into the field. Today our military is not much larger than in 2001; even if one includes the entire work force of the Department of Homeland Security, as well as the intelligence agencies, the total still amounts to less than 1 percent of the overall population. Yet in past wars, when the commander-in-chief was determined to win, he was willing to use any means necessary to build up strength, including a draft. That’s how, for example, the Union mobilized a full 10 percent of its population into uniform during the Civil War.

Another metric is war financing. Spending for defense and war has more than doubled in the past six years, from $292 billion in fiscal 2001 to somewhere around $650 billion this year. That’s a stupendous number, of course, but relative to the gross domestic product of nearly $14 trillion, it’s not so much — less than 5 percent, in fact. By comparison, at the peak of World War II, war spending was consuming almost 40 percent of our economic output.

And of course, taxes traditionally go up, too. During the Civil War, the income tax was imposed for the first time in our history. A half century later, when the United States entered World War I, the top federal income tax rate was a mere 7 percent. But it was immediately raised to 77 percent, and during World War II taxes were even higher, reaching 94 percent. By contrast, rates have been reduced over the past six years; the current top rate is 35 percent.

This is not to say that every politico-military decision of the Civil War and the two World Wars was wise. A strong argument can be made, for example, that too-high tax rates are outright counterproductive, because they discourage productive investing and encourage unproductive tax sheltering. But still, it’s hard to argue with success — the United States won those wars.

And remarkably, despite the tragic loss of life, the nation emerged substantially stronger from those wars. The Civil War saw not only the end to slavery, but also the beginnings of a transcontinental railroad system and the establishment of free higher education for the masses, in the form of land-grant colleges. Moreover, World War I established the United States as the world’s leading power. And in World War II, in addition to victory overseas, America established, on the home front, employment nondiscrimination as a national goal, even as it spawned whole new industries such as jet aviation and atomic power.

By contrast, the record over these past six years has been, shall we say, mixed. On the upside, the American homeland has not been attacked again, and the economy continues to grow. On the downside, the lack of commitment from the entire nation, top to bottom, has left us unable to develop the decisively war-winning strategies and technologies that characterized those earlier struggles.

Six years after 9/11, the world is watching us prosper at home — and flounder abroad. Such enemies and rivals as Iran, Russia and China are paying particularly close attention to our war-fighting effectiveness. They might well conclude that the United States is, as Chairman Mao once said, a paper tiger. That’s a dangerous judgment, for us and for the world.